Delineation of the European Armillaria species based on the sequences of the internal transcribed spacer (ITS) of ribosomal DNA

Abstract

Variation within the internal transcribed spacer (ITS) of the ribosomal RNA gene of 15 isolates representing seven European Armillaria species, was examined by sequencing of the PCR-amplified products. The analysis of an 744-bp region showed that the 5.8S gene appeared to be highly conserved in the 15 isolates and in other Basidiomycetes and Ascomycetes, whereas ITS1 and especially ITS2 spacers exhibited polymorphisms due to base substitutions, insertions or deletions of up to eight nucleotides. An initial dendrogram for the full sequence was drawn using cluster analysis (UPGMA), and a tree was constructed using the maximum parsimony method. Both methods indicated that the isolates could be divided into four major groups. One group, consisting of A. ectypa, was distinct from all the other species. Examination of the other groups indicated that A. tabescens and A. mellea were in a separated cluster, with a significant variation between the two isolates of the latter species. A. gallica and A. cepistipes constituted another closely related group distinguishable from A. ostoyae and A. borealis, these latter two species exhibiting the highest similarity. The results are consistent with, and discussed in regard to, the relationships estimated previously by pairing tests, morphological and physiological comparisons, as well as by restriction fragment length polymorphism of the rDNA.Key words : Armillaria, biological species, direct sequencing, internal transcribed spacer, phylogeny, ribosomal DNA. The genus Armillaria (Fr. : Fr.) Staude includes serious pathogens causing root rot of a broad host range of plants, all over the world. In Europe, there are seven intersterile groups or biological species (Korhonen, 1978 ;

Morphological, cultural, pathogenic and molecular studies of Alternaria brassicae infecting cauliflower and mustard in India

“…Due to the systematic and taxonomic usefulness the ITS region has been used in classifying fungi (Chillali et al, 1998) as it is suitable size for PCR amplification, restriction analysis and sequencing procedures, and because ITS regions are variable among species as well (Jung et al, 2002). Molecular relationships amongst Alternaria species based on nuclear ribosomal DNA and hostspecific toxins Tsuge, 1994, 1995) or with other related fungi have been analyzed (Pryor and Gilbertson, 2002;Chou and Wu, 2002).…”

Phylogenetic relationships among biological species of Armillaria from China

“…For phylogenetic inference, the internally transcribed spacer regions (ITS) and intergenic spacer region one (IGS-1) have been useful in studies focused on the relationships of taxa from Africa (Coetzee et al 2005a), South America (Pildain et al 2009), Australasia (Coetzee et al 2001), North America (Anderson and Stasovski 1992), Europe (Chillali et al 1998) and Asia (Terashima et al 1998;Coetzee et al 2000). In addition, sequences for part of the transcription elongation factor one alpha (TEF-1) gene has been used to determine the phylogenetic relationships of taxa from Japan (Hasegawa et al 2010), Europe (Tsykun et al 2013) and a global collection of isolates of Armillaria species (Maphosa et al 2006).…”

Identification protocol for sixArmillariaspecies from northeastern North America

“…Phylogenetic analysis and comparison of DNA sequences of rDNA regions (internal transcribed spacer (ITS) and intergenic spacer 1 (IGS1)) have been conducted on Armillaria spp. for the purposes of species identification or clarification of the taxonomic relationships among newly identified species within a specific region or country (Bhutan: Coetzee et al 2005) as well as for broader taxo-nomic studies (Northern Hemisphere: Anderson and Stasovski 1992;Europe: Chillali et al 1998a, 1998b. Restriction fragment length polymorophism (RFLP) analysis of the IGS1 region has also become a widely used species identification technique and has been used in several national and regional surveys (British Columbia, Canada: White et al 1998;Europe: Chillali et al 1998a); North America: Kim et al 2000; Serbia and Montenegro: Keča et al 2006) as well as for identification of species associated with root disease on specific hosts (Pinus spp.…”